alpha/gen/flt_rounds.c

1.10      wiz /* $NetBSD: flt_rounds.c,v 1.10 2014/08/03 19:14:24 wiz Exp $ */
 1.1      cgd
 1.1      cgd /*
 1.1      cgd  * Copyright (c) 1995 Christopher G. Demetriou
 1.1      cgd  * All rights reserved.
 1.4      cgd  *
 1.1      cgd  * Redistribution and use in source and binary forms, with or without
 1.1      cgd  * modification, are permitted provided that the following conditions
 1.1      cgd  * are met:
 1.1      cgd  * 1. Redistributions of source code must retain the above copyright
 1.1      cgd  *    notice, this list of conditions and the following disclaimer.
 1.1      cgd  * 2. Redistributions in binary form must reproduce the above copyright
 1.1      cgd  *    notice, this list of conditions and the following disclaimer in the
 1.1      cgd  *    documentation and/or other materials provided with the distribution.
 1.1      cgd  * 3. All advertising materials mentioning features or use of this software
 1.1      cgd  *    must display the following acknowledgement:
 1.4      cgd  *          This product includes software developed for the
 1.5     salo  *          NetBSD Project.  See http://www.NetBSD.org/ for
 1.4      cgd  *          information about NetBSD.
 1.1      cgd  * 4. The name of the author may not be used to endorse or promote products
 1.4      cgd  *    derived from this software without specific prior written permission.
 1.4      cgd  *
 1.1      cgd  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 1.1      cgd  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 1.1      cgd  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 1.1      cgd  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 1.1      cgd  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 1.1      cgd  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 1.1      cgd  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 1.1      cgd  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 1.1      cgd  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 1.1      cgd  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 1.4      cgd  *
 1.4      cgd  * <<Id: LICENSE,v 1.2 2000/06/14 15:57:33 cgd Exp>>
 1.1      cgd  */
 1.1      cgd
 1.7    lukem #include <sys/cdefs.h>
 1.7    lukem #if defined(LIBC_SCCS) && !defined(lint)
1.10      wiz __RCSID("$NetBSD: flt_rounds.c,v 1.10 2014/08/03 19:14:24 wiz Exp $");
 1.7    lukem #endif /* LIBC_SCCS and not lint */
 1.7    lukem
 1.1      cgd #include <sys/types.h>
 1.9     matt #include <machine/ieeefp.h>
 1.2  thorpej #include <machine/float.h>
 1.1      cgd
 1.9     matt /*
1.10      wiz  * These come from <float.h> definition
 1.9     matt  */
 1.9     matt #define	FLT_ROUND_MAP \
 1.9     matt 	( (0 << (FP_RZ*2))	/* round to zero */			\
 1.9     matt 	| (1 << (FP_RN*2))	/* round to nearest */			\
 1.9     matt 	| (3 << (FP_RM*2))	/* round to negative infinity */	\
 1.9     matt 	| (2 << (FP_RP*2)))	/* round to positive infinity */
 1.1      cgd
 1.1      cgd int
 1.9     matt __flt_rounds(void)
 1.1      cgd {
 1.9     matt 	union {
 1.9     matt 		double d;
 1.9     matt 		uint64_t u64;
 1.9     matt 	} fpcrval;
 1.9     matt 	uint64_t old;
 1.1      cgd
 1.9     matt 	__asm("excb; mf_fpcr %0; excb" : "=f" (fpcrval.d));
 1.9     matt 	old = (fpcrval.u64 >> 58) & 3;
 1.1      cgd
 1.9     matt 	return (FLT_ROUND_MAP >> (old << 1)) & 3;
 1.1      cgd }